Temperature dependence of the structure of a 0.06 mole fraction tertiary butanol-water solution

Hydrogen/deuterium isotopic substitution neutron diffraction techniques have been used to measure the solute-solute, solute-solvent and solvent-solvent structural correlation functions in a 0.06 mole fraction solution of tertiary butanol in water. The measurements were made at two temperatures, 25 degreesC and 65 degreesC. Data analysis to the level of intermolecular orientational correlation functions was performed by the Empirical Potential Structure Refinement (EPSR) technique in combination with a spherical harmonic coefficient analysis. The results reveal in particular a subtle temperature dependence of the intermolecular structure of the solvent water. This structural perturbation is suggestive of a hydrophobic hydration induced, local density enhancement in the solvent water that could relate to the entropic driving force underlying the hydrophobic interaction mechanism. (C) 2001 American Institute of Physics.